What is the ruling on the vow: "I promise You, my Lord, I will not marry, and I am coming to You as a martyr"?

A Muslim is obligated to fulfill promises, and Allah’s promise is most worthy of fulfillment. A promise that contravenes the Sunnah should not be fulfilled, and it is not an oath, so no expiation is required for it. One should seek forgiveness and repent, and marriage is in compliance with the command of the Messenger of Allah, peace and blessings be upon him: "O young people, whoever among you can afford to marry, let him do so, for it helps him lower his gaze and guard his chastity." Marriage does not contradict praiseworthy objectives; rather, it can be a means to achieve them. The Prophet, peace and blessings be upon him, and his companions were married, and they were the most pious of people. In summary: this promise does not have to be fulfilled, and it is better to follow the Sunnah.